Method of making a flexible sterile closure system for containers

Abstract

A sealing cover has an upper layer of plastic film substantially impervious to moisture and bacteria. A second layer of metal foil film is bonded to the plastic layer with a layer of adhesive or by extruding the plastic onto the second layer. An additional layer of adhesive material is bonded to the second layer for adhering to a carrier liner in packaging the seal and engaging the container top in resealing the container upon removal from the carrier. Upon removal of the sealing cover from a container, telltale strips of the cover are left in engagement with the container to indicate the seal has been removed. In another embodiment, a layer of metal foil is laminated between two layers of plastic film. Slits may be formed in the cover to promote its tearing to leave telltale sealing strips on the container upon removal of the cover. In another embodiment, a single layer of metal foil substantially impervious to moisture and bacteria includes a layer of adhesive material for an adhesive-coated surface for resealing the top of a container.

I claim: 
     
       1. The method of assembling a thin film closure for resealing a container, comprising: bonding a first layer of plastic film to a second layer of plastically deformable film with a layer of adhesive, at least one of said first or second layers being substantially impervious to moisture and bacteria;   forming a cover region and pull-tab region from said bonded first and second layers;   applying a layer of adhesive material to the exposed major surface of said second layer to form an adhesive-coated bottom surface of the cover;   slitting the cover region adjacent said pull-tab region to form a tear line for promoting the tearing of the cover upon its removal from the container;   attaching the adhesive-coated bottom surface of the cover to a carrier liner;   packaging the attached sealing cover and carrier liner; and   sterilizing the packaged sealing cover and carrier liner.   
     
     
       2. The method of assembling a thin film closure of claim 1 and further comprising: printing indicia on the upper surface of said first layer with an alcohol-resistant ink, said indicia relates to the containers to be sealed with the closure.   
     
     
       3. The method of assembling a thin film closure in claim 1 and further comprising: printing indicia on the surface of said first layer opposing said second layer prior to bonding said first and second layer, whereby said printed indicia relates to the containers to be sealed with the covers.   
     
     
       4. A method of assembling a thin film closure in claim 1 wherein said first layer is transparent and further comprising: printing indicia on the surface of said second layer opposed to said first layer prior to bonding said first and second layer, whereby said indicia relates to the containers to be sealed with the covers.   
     
     
       5. The method of assembling a thin film closure of claim 1, wherein said first layer is a transparent plastic film and further comprising: adding a dye material to the adhesive material bonding said first and second layers, whereby said dyed adhesive material provides means for color coding the closures.   
     
     
       6. The method of assembling a thin film closure for resealing a container, comprising: adhesively bonding a first layer of flexible plastic material to a second layer of metallic foil;   adhesively bonding said second layer of metallic foil to a third layer of flexible plastic material, at least one of said first, second or third layers being substantially impervious to moisture and bacteria;   forming a cover region and pull-tab region for the cover from the laminated structure of said first, second and third layers;   coating the exposed major surface of said third layer with an adhesive material to form an adhesive-coated bottom surface of the cover;   slitting the cover region adjacent said pull-tab region to form a tear line for promoting the tearing of the cover upon its removal from the container;   attaching the adhesive-coated bottom surface of the cover to a carrier paper;   packaging the attached sealing cover and carrier paper; and   sterilizing the packaged cover and carrier paper.   
     
     
       7. The method of assembling a thin film closure of claim 6 and further comprising: printing indicia on the upper surface of said first layer with an alcohol-resistant ink, said indicia relates to the containers to be sealed with the closure.   
     
     
       8. The method of assembling a thin film closure in claim 6 and further comprising: printing indicia on the surface of said first layer opposing said second layer prior to bonding said first and second layers, whereby said printed indicia relates to the containers to be sealed with the covers.   
     
     
       9. A method of assembling a thin film closure in claim 6 wherein said first layer is transparent and further comprising: printing indicia on the surface of said second layer opposed to said first layer prior to bonding said first and second layers, whereby said indicia relates to the containers to be sealed with the covers.   
     
     
       10. The method of assembling a thin film closure of claim 6 and further comprising: forming a non-adhesive region on the adhesive-coated bottom surface of the cover.   
     
     
       11. The method of assembling a thin film closure of claim 6 and further comprising: forming a non-adhesive region on the adhesive-coated bottom surface of the cover by printing a predetermined pattern adhesive on the exposed major surface of said third layer.   
     
     
       12. The method of assembling a thin film closure for resealing a container, comprising: extruding a first layer of plastic material onto a layer of metallic foil, said plastic or foil layer being substantially impervious to moisture and bacteria;   forming a cover region and pull-tab region from said plastic-coated metallic foil;   applying a layer of adhesive material to the uncoated major surface of said metallic foil to form an adhesive-coated bottom on the cover;   slitting the cover region adjacent said pull-tab region to form a tear line for promoting the tearing of the cover upon its removal from the container;   attaching the adhesive-coated bottom surface of the cover to a carrier paper;   packaging the attached cover and carrier paper; and   sterilizing the packaged cover and carrier paper.   
     
     
       13. The method of assembling a thin film closure for resealing a container, comprising: extruding layers of plastic material onto both major surfaces of a layer of metallic foil, said foil or plastic layers being substantially impervious to moisture and bacteria;   coating one of the plastic-coated major surfaces of said metallic foil with an adhesive material to form an adhesive-coated bottom surface of the cover;   forming a cover region and pull-tab region from the plastic-coated metallic foil;   cutting slits from the cover region adjacent said pull-tab region for a tear line to promote tearing of the cover upon its removal from the container;   attaching the adhesive-coated bottom surface of the cover to a carrier paper;   packaging the cover and carrier paper; and   sterilizing the packaged cover and carrier paper.